Bone marrow failure syndromes are severe hematologic diseases which can cause death due to low blood counts. Recent clinical experiences and laboratory experiments have indicated that the discrete syndromes of aplastic anemia (AA), paroxysmal nocturnal hemoglobinuria (PHN) and myelodysplastic syndromes (MDS) are closely related in their fundamental pathophysiology, natural history, and responsiveness to therapies. The Aplastic Anemia & MDS International Foundation (AA&MDSIF) is planning an "Bone Marrow Failure Scientific Symposium" to help advance research into these diseases. The Principal Investigator will be Jaroslaw Maciejewski, M.D. of the Cleveland Cancer Center, who will co-organize the conference with Neal S. Young, M.D. of the intramural National Heart, Lung, and Blood Institute. This two day international conference will feature presentations and interactions among leading researchers investigating these rare bone marrow failure syndromes; basic scientists in cell biology and immunology; epidemiologists, and academic clinicians, under the auspices of an academic center, a patient advocacy organization, and the NIH. Emphasis will be placed on bidirectional translational studies--bench to bedside and back--and the incorporation of themes and hypotheses previously confined to specific disease entities, but now more generally applicable, especially mechanisms of of hematopoietic cell destruction and apoptosis, genetic and geographic risk factors, and novel treatments based on immunosuppression and stem cell transplantation. The conference would be held in Summer/Fall 2004 in Annapolis, MD. Twenty-Four researchers would be invited to present their research in 30-minute sessions followed by 15 minutes of questions and open discussion. An estimated 200 researchers and other interested parties are expected to attend. The conference would conclude with a general forum to discuss lessons learned. Session abstracts and a conference summary would be distributed to attendees. A monograph would result from this event.